On Fri, 4 Nov 2005, Prof Brian Ripley wrote: > On Fri, 4 Nov 2005, Douglas Bates wrote: > >> On 11/4/05, Tom Van Dooren <[EMAIL PROTECTED]> wrote: >> >>> when running lmer with family set to quasibinomial, >>> is the "residual" variance reported among the random effects, the >>> dispersion parameter as in glm, or something else? >> >> It should be the dispersion parameter. I say "should be" because I am >> not that familiar with the quasibinomial family and I don't know >> exactly how the dispersion parameter is defined. I can tell you that >> the 'residual' variance is evaluated as the ML estimate of the >> variance from the last weighted penalized least squares problem used >> in the iterative estimation. Does that help? > > I would say that is an estimate of the dispersion parameter, different > from those used in glm() as indeed it should be as this is a GLM. ^not Oops, sorry.
> Estimation of the dispersion in a quasibinomial family is pretty tricky, > even for a glm. Be prepared for estimates to be biased. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html